This invention relates to an inner burr cutting, inner face cleaning and inner face painting apparatus for long pressure-welded pipes of small and medium diameters.
Steel pipes constituting, for example, a submarine or ground pipe line are recently pressure-welded. After pressure-welding, the customary practice is to cut off burrs produced on the inner and outer faces of the junctions of welded pipes. For removal of burrs from the inner faces of pressure-welded pipes, it is necessary first to cut off inner burrs by a cutter or similar tool and then clean the pipe interior by taking off burr chips or spatters produced during cutting or pressure-welding. Particularly, with steel pipes whose inner faces were previously painted, it is necessary to repaint those portions of the inner pipe faces from which burrs were cut off, or where the applied point was damaged by burning resulting from cutting heat or peeled off during the cutting operation.
An automatic inner burr cutting, inner face cleaning and inner face painting apparatus has been used which is provided with rotary cutters, cutter-pushing mechanism, cutter-rotating mechanism, rotary wire brush for cleaning and mechanism for rotating the wire brush. The cutting of inner burrs and the cleaning of the pipe interior have been effected by the single operation of the above-mentioned apparatus. However, such type of apparatus is designed for use with large diameter pipes and is consequently made into too large a size to be applied to long pressure-welded pipes of small and medium diameters.
With long pressure-welded pipes of small and medium diameters, therefore, inner burrs were formerly first cut off by an exclusive burr cutter. Thereafter, the pipe interior was cleaned by an exclusive cleaner. Consequently, the operation of cutting off inner burrs and cleaning the pipe interior failed to be carried out with high efficiency.
An exclusive inner burr cutter proposed to date is the type, wherein a shaft fitted with cutters at the forward end is inserted into long pressure-welded pipes of small and medium diameters; and while being rotated by an external drive mechanism, the shaft is axially moved to cut off inner burrs. With this type of inner burr cutter, there is the great possibility that while the shaft is taken into and out of pipes, the cutters fitted to the shaft strike against the inner faces of the pipes, probably resulting in the damage thereof. Where, therefore, the proposed inner burr cutter is applied to pipes whose inner faces were previously painted, it is necessary to repaint those portions of the pipe inner walls from which inner burrs were cut off, or which were damaged by the cutters fitted to the shaft. Consequently, a separate painting apparatus must be provided to repaint inner pipe faces. This repainting process not only reduces the overall efficiency of the inner pipe face-treating operation, but also is encountered with great difficulties due to the considerable length and relatively limited diameters of pipes being treated. After all, the above-mentioned exclusive inner burr cutter fails to be applied to long pressure-welded pipes of small and medium diameters whose inner faces were previously painted.
Further, a proposed exclusive cleaner for the inner faces of long pipes of small and medium diameters can not carry out efficient cleaning due to the great length and relatively limited diameters of pipes being treated, failing to fully clear inner pipe walls of burr chips and spatters.
Moreover, no measures have hitherto been taken to reduce the heat generated at the cutting of inner burrs and ensure the reliable repaint of the portions of inner pipe faces from which burrs were cut off.
The object of this invention is to provide an inner burr cutting, inner face cleaning and inner face painting apparatus for long pressure-welded pipes of small and medium diameters which carries out all these processes by a single operation.